The disclosures herein relate generally to computer systems and more particularly to establishing a thermal bond with a thermal interface material for computer system components.
To establish a good thermal bond between two mechanically fastened parts, a thermal interface material is needed to ensure maximum surface to surface contact. There are three types of industry standard thermal interface materials including a thermal pad, phase change material and thermal grease. In comparison to the thermal pad, thermal grease and phase change thermal interface material can have up to 10 times less thermal resistance. The reason for this is partially because the thermal grease and the phase change material are "flowable" materials. They flow to conform to all surface imperfections to achieve maximum thermal bonding.
Although the Flowable Thermal Interface Material (FTIM) works well, the measured application is difficult in a mass production environment. The key to applying the FTIM is to apply an accurate amount on the proper area. Presently, there is no known method to perform the accurate volumetric measurement and positioning of the thermal grease on the central processing unit (CPU) die on the computer production line. Occasionally, a system requires CPU replacement in the field. If the system uses a FTIM between the CPU and the heat block, the FTIM will need to be replaced when the CPU is replaced. In the field service scenario, the accurate application of the FTIM is even more difficult. Currently, experienced, trained operators perform the application of the flowable thermal interface material, which is not well controlled in terms of volume or location of the material Also, if a gasket is to be used to limit depletion of the FTIM, the originally installed gasket will take a thermal set after a period of time and cannot be satisfactority re-used if aftermarket replacement is required.
Thermally compliant material is disclosed in U.S. Pat. No. 5,568,360. A heat transfer system is provided for dissipating thermal energy within a personal computer. The transfer system is designed to move heat from a heat source, such as a CPU, to a heatsink arranged upon the portable computer keyboard. The heat transfer mechanism includes a heat slug thermally coupled to the CPU heat source and a heat pipe thermally coupled to a backside surface of a computer keyboard. The heat pipe is designed having minimal thermal gradient, and includes an evaporation/condensation cycle associated with its operation. The heat pipe is preferably orthogonally shaped having at least one flat surface arranged near the intersection of the orthogonal members. The flat section is in registry with a heat source. Movement of the flat section relative to the heat source effectuates abutment and thermal contact therebetween. The present thermal energy transfer system is designed for enhanced heat transfer within a portable computer system without undergoing the disadvantages of bulky finned heatsinks and/or fans.
Therefore, what is needed is a self-contained flowable thermal interface material module which retains the interface material in a reservoir and which can be installed as original equipment or as a replacement part.